A hinge serves as the pivotal connection between the door and its frame, allowing for smooth opening and closing motion. Hinges consist of two plates joined by a pin or rod, with one plate attached to the door and the other to the door frame. This design enables the door to swing freely while providing stability and support. Door hinges come in various types, including butt hinges, continuous/piano hinges, and concealed hinges, each offering distinct benefits and suitable for different door applications.